The invention relates to a soil cultivation device movable in a direction relative to the ground for subsoil loosening, having the features as set forth in the preamble of the attached claim 1.
Such soil cultivation devices are marketed in a variety of different versions and known from a plurality of patent documents such as, for example, DE 196 55 123 C2, WO 98/05191, EP 1 040 741 A2, EP 0 853 869 B1 and also EP 0 037 595 A1, all of them incorporated herein by reference.
The basic principle of such soil cultivation devices is described, for example, in EP 0 853 869 B1.
These soil cultivation devices are, for example, movably mounted articulated on a tow vehicle for riding over the ground. For example, the soil cultivation device can be mounted articulated on a reciprocating three-point linkage of a tractor or hitched trailing a tow vehicle. Soil cultivation devices have as a rule a frame (also termed chassis) for riding the ground on wheels, rollers or cylinders. These soil cultivation devices include a series of tool units for soil cultivation oriented perpendicular to the forward direction (traveling direction). Each of the tool units has (at least) one supporting arm pivotally mounted on the device chassis for reciprocation via a driving means such as particularly a crank assembly. At the other end of the supporting arm a piercing or perforating tool is articulated, for which, as a rule, a tool holder is provided as a perforating tool articulating means in which a perforating tool such as for example a tine or tine assembly or a hollow spoon or perforating tool units in the form of a bed of nails can be fixedly secured. These tool holders are pivotally articulated at the supporting arm.
As evident from FIGS. 2 and 3 of EP 0 853 869 B1 and the description thereof, lowering the supporting arms causes the perforating tool to perforate the ground. When the soil cultivation device travels further forwards, the perforating tools initially remain in the ground in the down position of the supporting arm and are pivoted relative to the supporting arm by the resistance. In this arrangement the tool holder or more generally the perforating tool articulating means is pivoted relative to the supporting arm. In all currently known generic soil cultivation devices, a stop is provided for each perforating tool or for each perforating tool holder against which each perforating tool or perforating tool holder is biased by a biasing device. In the pivoting of the perforating tool articulating means relative to the supporting arm with the tool in the ground, further traveling of the soil cultivation device causes the tool holder or an element articulated thereto to leave the stop. Then, when the supporting arm is again lifted and the soil cultivation device travels further in the forward direction, the perforating tool is drawn out of the ground and the biasing device pulls the perforating tool articulating means against the stop.
These stops and biasing devices are designed differently in prior art. As it reads from EP 0 853 869 B1 and EP 0 037 595 A1 the biasing device and the stop are configured on a telescopic rod which changes its position in operation by being reciprocated parallel to the supporting arm. In the devices as known from DE 196 55 123 C2, WO98/05191 as well as EP 1 040 741 A2, separate springs bias the tool holders against a stop provided at a setting lever.
Various attempts have been made in prior art to handle the movement of the perforating tool articulating means relative to the supporting arm, namely to bias, damp or to control and set such relative movement. It is known in particular to adjust the position of each stop to thus set the angle at which the perforating tool perforates the ground.
Movement handling means known hitherto for handling such movements are complicated in design. In addition, such handling means are also exposed to heavy wear because of the considerable amount of dirt as may materialize, particularly in hollow spoon operation. Apart from this, there is a limit to the working speed of the known devices.